AVS 46th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoP

Paper TF-MoP8
Diamond Formation Using a Low-Pressure Inductively Coupled Plasma

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: H. Ito, Nagoya Municipal Industrial Research Institute, Japan
Authors: H. Ito, Nagoya Municipal Industrial Research Institute, Japan
K. Teii, Nagoya University, Japan
M. Ito, Wakayama University, Japan
M. Hori, Nagoya University, Japan
T. Takeo, Nagoya Municipal Industrial Research Institute, Japan
T. Goto, Nagoya University, Japan
Correspondent: Click to Email
Diamond was successfully synthesized by using a H@sub 2@-rich CH@sub 4@/CO/H@sub 2@ and H@sub 2@-rich CH@sub 4@/H@sub 2@ inductively coupled plasma at a low pressure of 11 Pa. The ratio of particle size to deposition time, which is a criterion of the diamond growth rate, in H@sub 2@-rich CH@sub 4@/CO/H@sub 2@ mixture gas plasmas was larger than that in H@sub 2@-rich CH@sub 4@/H@sub 2@ mixture gas plasmas. The nondiamond phases in the deposits increased as CO gas was added to H@sub 2@-rich CH@sub 4@/H@sub 2@ mixture gas as observed by the Raman spectra. In order to investigate the mechanism for the diamond formation, C-atom densities in the plasmas were measured by using a vacuum ultraviolet absorption spectroscopy. In addition CH, OH, H-atom emission intensities were measured by optical emission spectroscopy. As a result, the C-atom densities and OH emission intensity increased with increasing the mixture ratio of CO to CH@sub 4@, while CH and H-atom emission intensities were almost constant. The generation of C-atoms from CO gases was much larger than that from CH@sub 4@. On the basis of the correlation between the quality of deposits and the C-atom densities in the plasma, C-atoms were found to contribute to form amorphous carbon phases rather than diamond phase. Moreover, using the low-pressure inductively coupled diamond formation plasmas, the importance of the abstraction of diamond surface-bonded H-atoms by OH radicals was suggested.